举一反三
- 5.下列函数中,在其定义域上有最大值和最小值的是()。 A: $f(x)=\left\{ \begin{array}{*{35}{l}} \ln \left| x \right|,\ \ \ x\ne 0 \\ 0,\ \ \ \ \ \ \ \ x=0 \\ \end{array} \right.$ B: $f(x)=\ln \left( \left| x \right|+1 \right)\ x\in [-1,1]$ C: $f(x)=\ln \left| x \right|,\ \ \ x\in [-1,1]\backslash \{0\}$ D: $f(x)=\left\{ \begin{array}{*{35}{l}} \ln \left| x \right|,\ \ \ 0\lt |x|\lt 1 \\ 0,\ \ \ \ \ \ \ \ x=0 \\ \end{array} \right.$
- 1. $\int \frac{1}{x(1+x)} dx =$ A: \[\ln{(x)}-\ln{\left( x+1\right) }+C\] B: \[\ln{(x)}+\ln{\left( x+1\right) }+C\] C: \[x-\ln{\left( x+1\right) }+C\] D: \[-\ln{(x)}+\ln{\left( x+1\right) }+C\]
- \( \int {\sec xdx} \)=( )。 A: \( \ln \left| {\csc x + \tan x} \right| + C \) B: \( \ln \left| {\sec x + \cot x} \right| + C \) C: \( \ln \left| {\sec x + \tan x} \right| + C \) D: \( \ln \left| {\csc x + \cot x} \right| + C \)
- 函数$y = \ln x$,则${\left( {\ln x} \right)^{\left( n \right)}} = {\left( { - 1} \right)^{n - 1}}{{\left( {n - 1} \right)!} \over {{x^n}}}$。( )
- 函数\(z = {\left( {xy} \right)^x}\)的全微分为 A: \(dz = \left( { { {\left( {xy} \right)}^x} + \ln xy} \right)dx + x{\left( {xy} \right)^x}dy\) B: \(dz = \left( { { {\left( {xy} \right)}^x} + \ln xy} \right)dx + { { x { { \left( {xy} \right)}^x}} \over y}dy\) C: \(dz = {\left( {xy} \right)^x}\ln xydx + { { x { { \left( {xy} \right)}^x}} \over y}dy\) D: \(dz = {\left( {xy} \right)^x}\left( {1 + \ln xy} \right)dx + { { x { { \left( {xy} \right)}^x}} \over y}dy\)
内容
- 0
\( \lim \limits_{x \to {0^ + }} {\left( {\cot x} \right)^ { { 1 \over {\ln x}}}} \)=_____ ______
- 1
\( \int {({1 \over x} - {2 \over {\sqrt {1 - {x^2}} }})dx} = \)( ) A: \( \ln \left| x \right| + 2\arcsin x + C \) B: \( \ln \left| x \right| - 2\arcsin x + C \) C: \(- \ln \left| x \right| - 2\arcsin x + C \) D: \(- \ln \left| x \right| +2\arcsin x + C \)
- 2
若连续函数\(f\left( x \right)\)满足关系式\(f\left( x \right) = \int_0^{2x} {f\left( { { t \over 2}} \right)} \,dt + \ln 2\),则\(f\left( x \right)\)等于( )。 A: \({e^{2x}}\ln 2\) B: \({e^x}\ln 2\) C: \({e^x} + \ln 2\) D: \({e^{2x}} + \ln 2\)
- 3
设\( A \)为\( n \) 阶方阵, \( B \)是\( A \)经过若干次初等变换后得到的矩阵,则( ) A: \( \left| A \right| = \left| B \right| \) B: \( \left| A \right| \ne \left| B \right| \) C: 若\( \left| A \right| = 0 \) ,则必有 \( \left| B \right| = 0 \) D: 若\( \left| A \right| > 0 \),则一定有\( \left| B \right| > 0 \)
- 4
下列函数中( )不是方程\( y' + xy = 0 \)的解。 A: \( y = {e^{ - { { {x^2}} \over 2}}} \) B: \( \ln \left| y \right| = - { { {x^2}} \over 2} \) C: \( y = {e^{ - { { {x^2}} \over 2}}} + 2 \) D: \( \ln \left| y \right| = - { { {x^2}} \over 2} +2\)